As modern technology has developed, new surgical innovations have followed the technology. One of the techniques of modern surgery that has rapidly grown in the last decade is the use of small openings in the body through which access to the internal organs is obtained. While many different titles to describe this technique have been used, probably the more common titles are laparoscopic surgery or endoscopic surgery. Other people prefer more descriptive titles such as telescopic surgery or minimally invasive surgery. This entire area of surgical techniques probably developed the most in laparoscopic cholecystectomy, which is used to remove gall stones.
For the present application, because the most commonly used and comprehensive term is endoscopic surgery, the term endoscopic surgery will be used in this application to refer collectively to all of these types of surgery. However, it should be realized that other terms can be used to describe the surgical technique.
In endoscopic surgery, a small cut is made in the skin and a sharpened cannula or spike is then inserted through the fascia into a body opening such as the abdominal cavity. After removal of the spike from the cannula, the cannula will then allow access to the body opening such as the abdominal cavity.
Typically, a gas is inserted through the cannula to insufflate the body opening. Once the first opening is made, a camera lens on the end of a fiber optic cable can be inserted through the cannula that will allow the monitoring of the internal parts of the body cavity. It is extremely important that the body organs not be damaged when inserting any cannulas, spikes, or trocars into the body.
After access to the body opening is obtained by the insertion of the cannula, it is also important to maintain a seal along the central opening of the cannula. If not, the gas used for the insufflation of the body cavity will rapidly escape and it will be difficult to maintain a sufficient cavity opening for the endoscopic surgery.
In the past, various types of seals have been developed to seal the upper part of the cannula opening. An example is shown in U.S. Pat. No. 5,512,053, which patent is owned by the same assignee as the present application. U.S. Pat. No. 5,512,053 provides a lip seal to maintain the insufflation gas in the body cavity. However, once a medical instrument is inserted through the lip seal, the gas can leak around the medical instrument and escape into the atmosphere. To provide a back up, a second sliding seal with different size apertures has been provided to engage the medical instrument being inserted into the cannula and through the lip seal. Medical instruments vary in size, and the medical instruments will be moved from side to side during use in endoscopic surgery. This side to side motion causes leakage of the gas around the medical instruments. Some type of seal is needed that will seal around medical instruments of varying sizes and, at the same time, allow for lateral or side to side movement of the medical instrument during endoscopic surgery.
Also, it is important that the seal have a memory to return to its original position after periods of use. In other words, if the doctor during the operation is moving the medical instrument to one side, there should be a continual force trying to urge the medical instrument back to the center of the cannula opening.
To remedy the problem of different size medical instruments being inserted through the cannula, U.S. Pat. No. 4,112,932 shows a laparoscopic cannula that has a rotating seal where different size openings can be selected depending upon the size of instrument being inserted into the cannula. While this is effective to some degree, it does not allow for side to side movement of the medical instrument and it does not allow for the rapid exchange of medical devices without also rotating or spinning the seal.
A common seal that is in use today to seal surgical instruments such as cannulas, trocars, or similar devices is shown in U.S. Pat. No. 5,407,433 to Loomas. The Loomas patent and its related patents allows some side to side movement of the medical instruments, but has a rigid internal ring on the seal that limits its effectiveness. The rigid internal ring does not allow the seal to make a sealing relationship with the medical instrument as well as the present invention. The inflexible nature of the internal ring does not provide as effective an urging force against the medical instrument to return the medical instrument to the center of the cannula. The Loomas seal is also much more complicated and expensive to manufacture than the present universal seal and does not provide as effective sealing as the present invention.
To overcome this problem of accommodating different sizes of medical instruments and to allow for side to side movement, many other United States patents have been issued to seal surgical instruments such as cannulas or trocars. Another example is U.S. Pat. No. 5,342,315 issued to Rowe, which has a whole collection of different types of seals. Each of these seals is much more complicated and expensive to manufacture than the present invention and still is not as effective. The Rowe patent shows all types of reinforcing ribs and slots being cut in the seal, none of which are necessary with the present invention.
Other patents refer to their seal as a "universal seal" such as U.S. Pat. No. 5,628,732 to Antoon or U.S. Pat. No. 5,350,364 to Stephens. Again, both of these patents are much more complicated, expensive, and do not do the job of the present universal seal. Applicants, who are very familiar with the industry, do not know of any other seal that is as economical and inexpensive to manufacture as the present universal seal, but is as effective in allowing different size instrument to be inserted through a cannula and allowing side to side movement of the medical instrument, yet still maintaining air tight contact to hold the insufflation gas inside the body cavity. The need exists for a universal type of seal that can be used for any cannula or trocar device through which access is obtained to body cavities for the purpose of performing endoscopic surgery, particularly while sealing against the surgical instruments being inserted through the cannulas or trocars into the body.